A former Dallas charter school teacher has been sentenced to two 40-year prison sentences for sexually assaulting students in 2012.

Geogery Lynn Shelton

(Lew Sterrett Justice Center/)

Geogery Lynn Shelton, 46, who taught at the Children's First Elementary Academy in southeast Oak Cliff, also received a 15-year sentence Friday for indecency with a child by contact. He was indicted on the charges in February 2013.

The incidents involved two 12-year-old male students and took place on campus, in a classroom and in a school bathroom, according to police documents. A separate incident reportedly occurred in a hotel room during a school field trip to San Antonio.

One boy told investigators that Shelton called him into the classroom, pulled down his shorts and performed oral sex. According to the documents, Shelton told him: "I know you're not like that, but I just can't help myself."

"We continue to pray these families will heal from these horrific crimes," said Dallas County District Attorney Faith Johnson. "Parents send their children to school believing they will be protected, not victimized."